The proposed study will conduct a 20-year long-term follow-up of opiate-dependent women (n = 337), and will examine gender differences in the addiction careers of this cohort of women and a comparable sample of men (n = 584). The subjects were originally sampled from methadone maintenance clinics in six Central and Southern California counties in the late 1970s, and study findings will be interpreted within the context of treatment and social policies implemented within the state. In-depth natural history interviews, as part of two separate studies, were conducted with this sample in 1978--81. The natural history database established by this initial assessment will be extended by the proposed work, covering an additional period of approximately 20 years. The follow-up interview will assess drug use, criminal behavior, treatment participation, health status, and psychosocial functioning over this extended follow-up period. Interview data will be augmented with archival treatment and criminal justice records. The study will examine gender differences in the factors that influence relapse to and cessation of opiate use over the course of the addiction career; the relationship of psychosocial functioning to identified patterns of use and abstinence; patterns of criminal activity, arrest, incarceration, and legal supervision; drug treatment utilization and other social interventions and associated outcomes; health status and health services utilization; and predictors and correlates of mortality. Death certificates will be obtained for deceased subjects and standard mortality ratios will be computed for gender differences within the sample and in comparison to the general population. The study will provide the longest follow-up study of women opiate users ever performed and will improve the understanding of gender differences in the long-term patterns and consequences of opiate use among this California-based treatment sample. The study findings have the potential to develop interventions aimed at opiate users that address the specific needs of males and females over the life course.